PMBus Serial Digital Interface ...............................................................................................................................16
Register Command Set ..........................................................................................................................................18
Manufacturer Specific Commands .........................................................................................................................35
Other Operations....................................................................................................................................................49
Applications Information ....................................................................................................... 50
PCB Assembly and Layout Suggestions ................................................................................................................61
Related Parts ..................................................................................................................... 64
2978fa
LTC2978
absoluTe MaxiMuM raTings
(Notes 1, 2)
pin conFiguraTion
64 V
SENSEP6
63 V
SENSEM5
62 V
SENSEP5
61 V
DACM7
60 V
DACP7
59 V
DACP6
58 V
DACM6
57 V
DACM5
56 V
DACP5
55 V
DACP4
54 V
DACM4
53 V
SENSEM4
52 V
SENSEP4
51 V
DACM3
50 V
DACP3
49 V
SENSEM3
V
SENSEM6
1
V
SENSEP7
2
V
SENSEM7
3
V
OUT_EN0
4
V
OUT_EN1
5
V
OUT_EN2
6
V
OUT_EN3
7
V
OUT_EN4
8
V
OUT_EN5
9
V
OUT_EN6
10
V
OUT_EN7
11
V
IN_EN
12
DNC 13
V
IN_SNS
14
V
PWR
15
V
DD33
16
65
48 V
SENSEP3
47 V
SENSEM2
46 V
SENSEP2
45 V
DACM2
44 V
DACP2
43 V
SENSEM1
42 V
SENSEP1
41 V
DACM1
40 V
DACP1
39 V
DACP0
38 V
DACM0
37 V
SENSEM0
36 V
SENSEP0
35 REFM
34 REFP
33 ASEL1
UP PACKAGE
64-LEAD (9mm 9mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 28°C/W
EXPOSED PAD (PIN 65) IS GND, MUST BE SOLDERED TO PCB
TOP VIEW
Supply Voltages:
V
PWR
to GND ......................................... –0.3V to 15V
V
IN_SNS
to GND ..................................... –0.3V to 15V
V
DD33
to GND ....................................... –0.3V to 3.6V
V
DD25
to GND ..................................... –0.3V to 2.75V
Digital Input/Output Voltages:
ALERTB, SDA, SCL, CONTROL0,
CONTROL1............................................ –0.3V to 5.5V
PWRGD, SHARE_CLK,
WDI, WP ..................................–0.3V to V
DD33
+ 0.3V
FAULTB00, FAULTB01, FAULTB10,
FAULTB11 ................................–0.3V to V
DD33
+ 0.3V
ASEL0, ASEL1 ..........................–0.3V to V
DD33
+ 0.3V
Analog Voltages:
REFP ................................................... –0.3V to 1.35V
REFM to GND........................................ –0.3V to 0.3V
V
SENSEP[7:0]
to GND ................................. –0.3V to 6V
V
SENSEM[7:0]
to GND ................................ –0.3V to 6V
V
OUT_EN[3:0]
, V
IN_EN
to GND .................. –0.3V to 15V
V
OUT_EN[7:4]
to GND ................................. –0.3V to 6V
V
DACP[7:0]
to GND .................................... –0.3V to 6V
V
DACM[7:0]
to GND ............................... –0.3V to 0.3V
Operating Temperature Range:
LTC2978C ................................................ 0°C to 70°C
LTC2978I .............................................–40°C to 85°C
Storage Temperature Range .................. –65°C to 125°C
orDer inForMaTion
LEAD FREE FINISH
LTC2978CUP#PBF
LTC2978IUP#PBF
TAPE AND REEL
LTC2978CUP#TRPBF
LTC2978IUP#TRPBF
PART MARKING*
LTC2978
LTC2978
PACKAGE DESCRIPTION
64-Lead (9mm
×
9mm) Plastic QFN
64-Lead (9mm
×
9mm) Plastic QFN
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
V
DD33
17
V
DD25
18
WP 19
PWRGD 20
SHARE_CLK 21
WDI/RESET 22
FAULTB00 23
FAULTB01 24
FAULTB10 25
FAULTB11 26
SDA 27
SCL 28
ALERTB 29
CONTROL0 30
CONTROL1 31
ASEL0 32
2978fa
LTC2978
elecTrical characTerisTics
SYMBOL
PARAMETER
Power-Supply Characteristics
V
PWR
V
PWR
Supply Input Operating Range
I
PWR
V
PWR
Supply Current
I
VDD33
V
DD33
Supply Current
V
UVLO_VDD33
V
DD33
Undervoltage Lockout
V
DD33
Undervoltage Lockout
Hysteresis
V
DD33
Supply Input Operating Range
Regulator Output Voltage
Regulator Output Short-Circuit Current
V
DD25
Regulator Output Voltage
Regulator Output Short-Circuit Current
Voltage Reference Characteristics
V
REF
Output Voltage
Temperature Coefficient
Hysteresis
ADC Characteristics
V
IN_ADC
Voltage Sense Input Range
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
PWR
= V
IN_SNS
= 12V, V
DD33
, V
DD25
and REF pins floating, unless
otherwise indicated. C
VDD33
= 100nF C
VDD25
= 100nF and C
REF
= 100nF
,
.
CONDITIONS
l
MIN
4.5
TYP
MAX
15
13
13
2.8
UNITS
V
mA
mA
V
mV
V
V
mA
V
mA
V
ppm/°C
ppm
4.5V ≤ V
PWR
≤ 15V, V
DD33
Floating
3.13V ≤ V
DD33
≤ 3.47V, V
PWR
= V
DD33
V
DD33
Ramping Up, V
PWR
= V
DD33
l
l
l
2.35
10
10
2.55
120
V
PWR
= V
DD33
4.5V ≤ V
PWR
≤ 15V
V
PWR
= 4.5V, V
DD33
= 0V
3.13V ≤ V
DD33
≤ 3.47V
V
PWR
= V
DD33
= 3.47V, V
DD25
= 0V
l
l
l
l
l
3.13
3.13
75
2.35
30
3.26
90
2.5
55
1.232
3
100
3.47
3.47
140
2.6
80
(Note 3)
Differential Voltage:
V
IN_ADC
= (V
SENSEPn
– V
SENSEMn
)
Single-Ended Voltage: V
SENSEMn
Single-Ended Voltage: V
SENSEPn
, V
SENSEMn
Differential Voltage: V
IN_ADC
0V ≤ V
IN_ADC
≤ 6V
0mV ≤ |V
IN_ADC
| < 16mV
16mV ≤ |V
IN_ADC
| < 32mV
32mV ≤ |V
IN_ADC
| < 63.9mV
63.9mV ≤ |V
IN_ADC
| < 127.9mV
127.9mV ≤ |V
IN_ADC
|
V
IN_ADC
≥ 1.8V (Note 4 )
Voltage Sense Mode (Note 5)
Current Sense Mode, Odd Numbered
Channels Only, 15.6µV/LSB (Note 5)
Voltage Sense Mode
Current Sense Mode, Odd Numbered
Channels Only
Voltage Sense Mode
Current Sense Mode, Odd Numbered
Channels Only
Voltage Sense Mode, V
IN_ADC
= 6V
Current Sense Mode, Odd Numbered
Channels Only, V
IN_ADC
= ±0.17V
Voltage Sense Mode (Note 6)
Current Sense Mode (Note 6)
Temperature Input (Note 6)
l
l
l
l
0
–0.1
–0.1
–170
122
15.625
31.25
62.5
125
250
6
0.1
6
170
V
V
V
mV
µV/LSB
µV/LSB
µV/LSB
µV/LSB
µV/LSB
µV/LSB
%
µV
µV
µV
µV
µV
µV
%
%
ms
ms
ms
pF
kHz
2978fa
N_ADC
Current Sense Input Range (Odd
Numbered Channels Only When So
Configured)
Voltage Sense Resolution
Current Sense Resolution (Odd
Numbered Channels Only When So
Configured)
Total Unadjusted Error
Integral Nonlinearity
TUE_ADC
INL_ADC
l
l
l
l
l
l
l
l
l
±0.25
±854
±31.3
±400
±31.3
±250
±35
±0.2
±0.2
6.15
24.6
24.6
1
62.5
DNL_ADC
Differential Nonlinearity
V
OS_ADC
Offset Error
GAIN_ADC
Gain Error
t
CONV_ADC
Conversion Time
C
IN_ADC
f
IN_ADC
Input Sampling Capacitance
Input Sampling Frequency
LTC2978
elecTrical characTerisTics
SYMBOL
I
IN_ADC
PARAMETER
Input Leakage Current
Differential Input Current
Voltage Buffered IDAC Output Characteristics
N_V
DACP
Resolution
V
FS_VDACP
Full-Scale Output Voltage
(Programmable)
INL_V
DACP
Integral Nonlinearity
DNL_V
DACP
Differential Nonlinearity
V
OS_VDACP
Offset Voltage
V
DACP
Load Regulation (V
DACPn
– V
DACMn
)
PSRR (V
DACPn
– V
DACMn
)
DC CMRR (V
DACPn
– V
DACMn
)
Leakage Current
Short-Circuit Current Low
Short-Circuit Current High
C
OUT
Output Capacitance
t
S_VDACP
DAC Output Update Rate
Voltage Supervisor Characteristics
V
IN_VS
Input Voltage Range (Programmable)
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
PWR
= V
IN_SNS
= 12V; V
DD33
, V
DD25
and REF pins floating, unless
otherwise indicated. C
VDD33
= 100nF C
VDD25
= 100nF and C
REF
= 100nF
,
.
CONDITIONS
V
IN_ADC
= 0V, 0V ≤ V
COMMONMODE
≤ 6V,
Current Sense Mode
V
IN_ADC
= 0.17V, Current Sense Mode
V
IN_ADC
= 6V, Voltage Sense Mode
MIN
l
l
l
TYP
MAX
±0.5
250
15
UNITS
µA
nA
µA
Bits
V
V
LSB
LSB
mV
ppm/mA
ppm/mA
dB
dB
dB
nA
mA
mA
pF
µs
V
V
V
mV/LSB
mV/LSB
%
%
%
µs
V
kΩ
%
%
%
%
mV
°C
80
10
10
1.38
2.65
DAC Code = 0x3FF Buffer Gain Setting_0
DAC Polarity = 1
Buffer Gain Setting_1
(Note 7)
(Note 7)
(Note 7)
V
DACPn
= 2.65V, I
VDACPn
Sourcing = 2mA
V
DACPn
= 0.1V, I
VDACPn
Sinking = 2mA
DC: 3.13V ≤ V
DD33
≤ 3.47V, V
PWR
= V
DD33
100mV Step in 20ns with 50pF Load
–0.1V ≤ V
DACMn
≤ 0.1V
V
DACPn
Hi-Z, 0V ≤ V
DACPn
≤ 6V
V
DACPn
Shorted to GND
V
DACPn
Shorted to V
DD33
V
DACPn
Hi-Z
Fast Servo Mode
V
IN_VS
= (V
SENSEPn
Low Resolution Mode
– V
SENSEMn
)
High Resolution Mode
Single-Ended Voltage: V
SENSEMn
0V to 3.8V Range: High Resolution Mode
0V to 6V Range: Low Resolution Mode
2V ≤ V
IN_VS
≤ 6V, Low Resolution Mode
1.5V < V
IN_VS
≤ 3.8V, High Resolution Mode
0.8V ≤ V
IN_VS
≤ 1.5V, High Resolution Mode
l
l
l
l
l
1.32
2.53
1.44
2.77
±2
±2.4
±10
100
100
60
40
60
l
l
l
–10
4
10
250
±100
–4
10
l
l
l
0
0
–0.1
4
8
6
3.8
0.1
N_VS
TUE_VS
Voltage Sensing Resolution
Total Unadjusted Error
l
l
l
±1.25
±1.0
±1.5
12.21
t
S_VS
Update Rate
V
IN_SNS
Input Characteristics
V
VIN_SNS
V
IN_SNS
Input Voltage Range
R
VIN_SNS
V
IN_SNS
Input Resistance
TUE
VIN_SNS
V
IN_ON
, V
IN_OFF
Threshold Total
Unadjusted Error
l
l
l
l
l
l
0
70
90
3V ≤ V
VIN_SNS
≤ 8V
V
VIN_SNS
> 8V
READ_V
IN
Total Unadjusted Error
3V ≤ V
VIN_SNS
≤ 8V
V
VIN_SNS
> 8V
Voltage Buffered IDAC Soft-Connect Comparator Characteristics
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